1. Field of the Invention
The present invention generally relates to a marine toilet system, and more particularly to a marine toilet system having a single bidirectional motor which drives a drive shaft, a first impeller mounted on the drive shaft for filling a toilet bowl with fluid and a second impeller mounted on the drive shaft for emptying fluid from the toilet bowl.
2. Discussion of the Related Art
Marine vessel toilet systems have several operational requirements which are different from household toilet systems. One difference is that the bowl of the marine vessel toilet system is generally dry when the toilet is not in use, since the motion of the marine vessel could cause any water in the bowl to splash out of the bowl. It is also desirable to minimize the amount of water used to fill the bowl when it is used. This is because the toilet bowl is often evacuated to a holding tank for later disposal. Therefore, it is important to keep the amount of water held in the holding tank to a minimum. Furthermore, in some cases, the water input to the toilet bowl is drawn from the marine vessel's fresh water supply, in order to minimize any odors. Due to the finite amount of fresh water which can be stored on a vessel, it is important to minimize the amount of water used to operate the toilet system.
There are several different prior art designs of toilets for use on marine vessels. One design include toilets which use one pump for pumping water into the bowl of the toilet and a second pump for pumping water and waste from the bowl. Since this design requires two pumps, the toilet system is very heavy, expensive and more prone to malfunctioning.
Other designs use a single pump to both pump water into the bowl and to pump it from the bowl. However, these toilets require the use of a number of valves which are manually set to control whether the filling or emptying operation is carried out while the motor is running. Some examples of this design are disclosed in U.S. Pat. Nos. 1,329,932 and 1,888,842. U.S. Pat. No. 3,035,274 discloses a toilet system which uses a single pump to fill and flush the toilet simultaneously. U.S. Pat. No. 3,478,690 discloses a toilet system which utilizes a bidirectional pump which rotates a shaft in opposite directions in order to break up solid waste in the water while directing the flow of the water in one direction only. U.S. Pat. No. 4,974,264 discloses a toilet system which utilizes a vacuum device for filling and flushing the toilet. This system also requires the use of a number of manual valves for controlling which function is to be carried out.
While these designs are effective in filling and flushing toilets, they can cumbersome to operate, can be very heavy and very inefficient, can take up a large amount of deck space on a marine vessel, are more prone to requiring maintenance and can be very expensive.
There is therefore a need for a marine toilet system which is simple to use, occupies less deck space, operates efficiently, is less expensive to manufacture and is less prone to requiring maintenance.